19 covers and folded letters from Hartford's short-lived "blue period" during which postmaster Normand Lyman switched from the city's usual magenta ink to blue, includes the earliest blue ink postmark (May 24, 1847) and continues through December of that same year, handstamps include "5" and "10" numerals, pointing hand "Paid", and "Steam", generally fine to very fine, an interesting study of this seven month period